In seeking the biological answer to the question of what it means to be human, the brain’s cerebral cortex is a good place to start. This densely folded, outer layer of grey matter, which is vastly larger in Homo sapiens than in other primates, plays an essential role in human consciousness, language, and reasoning.

Now, an NIH-funded team has pinpointed a key set of genes—found only in humans—that may help explain why our species possesses such a large cerebral cortex. Experimental evidence shows these genes prolong the development of stem cells that generate neurons in the cerebral cortex, which in turn enables the human brain to produce more mature cortical neurons and, thus, build a bigger cerebral cortex than our fellow primates.

That sounds like a great advantage for humans! But there’s a downside. Researchers found the same genomic changes that facilitated the expansion of the human cortex may also render our species more susceptible to certain rare neurodevelopmental disorders.

Over the past couple of weeks, we’ve lost two legendary scientists who made major contributions to our world: Sir John Sulston and Stephen Hawking. Although they worked in very different areas of science—biology and physics—both have left us with an enduring legacy through their brilliant work that unlocked fundamental mysteries of life and the universe.

I had the privilege of working closely with John as part of the international Human Genome Project (HGP), a historic endeavor that successfully produced the first reference sequence of the human genetic blueprint nearly 15 years ago, in April 2003. As founding director of the Sanger Centre (now the Sanger Institute) in Cambridge, England, John oversaw the British contributions to this publicly funded effort. Throughout our many planning meetings and sometimes stormy weekly conference calls about progress of this intense and all-consuming enterprise, John stood out for his keen intellect and high ethical standards.

It’s hard to believe, but it’s been almost 15 years since we successfully completed the Human Genome Project, ahead of schedule and under budget. I was proud to stand with my international colleagues in a celebration at the Library of Congress on April 14, 2003 (which happens to be my birthday), to announce that we had stitched together the very first reference sequence of the human genome at a total cost of about $400 million. As remarkable as that achievement was, it was just the beginning of our ongoing effort to understand the human genome, and to use that understanding to improve human health.

That first reference human genome was sequenced using automated machines that were the size of small phone booths. Since then, breathtaking progress has been made in developing innovative technologies that have made DNA sequencing far easier, faster, and more affordable. Now, a report in Nature Biotechnology highlights the latest advance: the sequencing and assembly of a human genome using a pocket-sized device [1]. It was generated using several “nanopore” devices that can be purchased online with a “starter kit” for just $1,000. In fact, this new genome sequence—completed in a matter of weeks—includes some notoriously hard-to-sequence stretches of DNA, filling several key gaps in our original reference genome.

When Julie Dunning Hotopp was a post-doctoral fellow in the early 2000s, bacteria were known for swapping bits of their DNA with other bacteria, a strategy known as lateral gene transfer. But the offloading of genes from bacteria into multicellular organisms was thought to be rare, with limited evidence that a bacterial genus called Wolbachia, which invades the cells of other organisms and takes up permanent residence, had passed off some of its DNA onto a species of beetle and a parasitic worm. Dunning Hotopp wondered whether lateral gene transfer might be a more common phenomenon than the evidence showed.

She and her colleagues soon discovered that Wolbachia had engaged in widespread lateral gene transfer with eight species of insects and nematode worms, possibly passing on genes and traits to their invertebrate hosts [1]. This important discovery put Dunning Hotopp on a research trail that now has taken a sharp turn toward human cancer and earned her a 2015 NIH Director’s Transformative Research Award. This NIH award supports exceptionally innovative research projects that are inherently risky and untested but have the potential to change fundamental research paradigms in areas such as cancer and throughout the biomedical sciences.

To celebrate the 10th anniversary of the completion of the Human Genome Project—a 13-year endeavor that I had the privilege of leading—the Smithsonian’s National Museum of Natural History in Washington, DC is launching an absolutely fantastic exhibit called “Genome: Unlocking Life’s Code.”

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About the NIH Director

Francis S. Collins, M.D., Ph.D.

Appointed the 16th Director of NIH by President Barack Obama and confirmed by the Senate. He was sworn in on August 17, 2009. On June 6, 2017. President Donald Trump announced his selection of Dr. Collins to continue to serve as the NIH Director.